I'm secondary so didn't share any classes as our subject gets everyone, once a week.
Yes I think it was harder in some ways as I didn't get the sheer volume of hours of practice in, in one go. I also missed out on key info, those important corridor conversations about little Johnny's mum being ill and the chance to keep on top of detentions missed by grabbing pupils the next day, as you tend to do.
The planning load is the same as FT as you need to plan for each year group, even if you only teach one class.
But, you get days off in between to unwind and de-stress! And fewer reports to write, fewer books to mark. It all helps.
This year I am 0.4 and have a year 11 class which I team teach with my HOD, a year 10 class I see twice, 4 year 8s, one of whom I team teach, and 2 year 7s. The team teaching is due to falling roll, in turn due to us being in SM. I also run clubs on both days I am in and have been excused from a weekly meeting after school as it's the only time I have available to run the club.
It gets easier with planning as you recycle and upgrade stuff from last year, (even if you do chuck out half of it, thinking "what was I thinking doing that! ) Nowadays I can do all planning on a Sunday early morning and late evenings so it's not eating into family time. I mark books during the week, on a. 2week cycle and refuse to work in the day when I am supposed to be a SAHM.
Re marking: regular small amounts are much easier, I sometimes have a set of books out on the kitchen worktop when cooking the tea, although I have had a couple of unfortunate splashes.
Self marking, peer marking, peer assessment and clear assessment criteria planned in advance are helpful. The kids prefer self and peer marking as they get instant feedback. Plus, our old head used to say "if you can't mark it, don't set it". Have answers on your PowerPoint ready to go, so things can be marked really quickly.
I keep a green pen blue-tacked to the whiteboard ready to go and as soon as I leave my upfront teaching position to walk round, I get in there with my green marking pen when I am monitoring class work and mark as much as possible there and then. I do my ticks backward when marking at home to distinguish from work marked in class, to 'prove' I am monitoring work in class, IYSWIM.